This study aims to establish a knowledge base on how to support students in learning. We develop an initial hypothetical learning trajectory by formulating learning activities and predicting the development of students' thinking and understanding. The methodological framework employed in this study is design research, which seeks to generate…

The task shared in this article provides geometry students with opportunities to recall and use basic geometry vocabulary, extend their knowledge of area relationships, and create area formulas. It is characterized by reasoning and sense making (NCTM 2009) and the "Construct viable arguments and critique the reasoning of others"…

We present a geometrical investigation of the process of creating an infinite sequence of triangles inscribed in a circle, whose areas, perimeters and lengths of radii of the inscribed circles tend to a limit in a monotonous manner. First, using geometrical software, we investigate four theorems that represent interesting geometrical properties,…

According to the National Council of Teacher of Mathematics (NCTM) (2000), K-12 students should be given an opportunity to develop their spatial reasoning abilities. One of the topics that may allow students to develop their spatial skills is forming 3-dimensional objects using spinning and extrusion methods. Also, extrusion and spinning methods…

In this article, associate professor Chrystal Dean describes how teachers can challenge their upper elementary students' understanding of area beyond a memorized formula. Herein she describes an activity that will show students the "why" behind using A = l × w to solve rectangular area problems. The activity will help deepen…

Learning about the area formulas provides many opportunities for students even at the beginning of junior secondary school to experience mathematical deduction. For example, in easy cases, students can put two triangles together to make a rectangle, and so deduce that the area of a triangle is half the area of a corresponding rectangle. They can…

This article contains investigative activities to assist students in constructing formulas out of an understanding of the area of geometric shapes. Included with this article are a "Finding Areas on Square Dot Paper Activity Sheet" and a "Finding Areas on Triangle Dot Paper Activity Sheet." (Contains 1 table and 11 figures.)

Flow diagrams developing cube roots and formulas for the square, sphere, cube, circle and sector, oblong, and cylinder are presented. Some comments on their use, along with calculators, are included. (MNS)

Cultivates a definition for the surface area of a sphere with successive approaches. The first utilizes the notion that a sphere cannot be "developed" in the mathematical sense that a cylinder can be cut, unrolled, and measured. The second considers approximations by polyhedra. The third uses Minkowski's definition to introduce the…

Illustrates various methods to determine the perimeter and area of triangles and polygons formed on the geoboard. Methods utilize algebraic techniques, trigonometry, geometric theorems, and analytic geometry to solve problems and connect a variety of mathematical concepts. (MDH)

Presented is an activity in which students apply familiar concepts of geometry to novel settings. Using square dot paper and isometric dot paper, students trace routes and determine the geometry of each circle. (KR)

Presents three stories from mathematics history that can be integrated into classroom teaching: (1) the account of how Eratosthenes measured the circumference of the earth to discuss the concept of units in measurement, (2) ideas from Archimedes, Vite, and Descartes to introduce pi, and (3) the discovery of the Cardanic formula as an example of…

In order to assist elementary and middle school teachers in teaching the skills associated with the concepts of perimeter, area, and volume, this addition to the National Council of Teachers of Mathematics "How to..." series is intended to supplement a text with practical information written in nontechnical language. Each chapter…

Presents activities to teach the formula for the area of a rectangle that require students to determine the cost of refurbishing their school's tennis courts. Students collect their own data, organize information, and make decisions individually and as a group to solve the problem. Worksheets are provided. (MDH)

Describes three activities to teach mathematical concepts involving probabilities related to outcomes using "Sicherman" and other dice; geometric representations of algebraic identities; and the volume of a cone. (MDH)